1. Field of the Invention
The present invention relates generally to forage harvesters for harvesting and chopping stalky crop irrespective of crop row placement relative to the harvester as it moves across a field (i.e., a so-called "non-row-sensitive forage harvester"). More particularly, the present invention concerns improved structure for controlling the flow of severed stalks as the stalks move through the header and are presented to the chopping device.
2. Discussion of Prior Art
It is often desired to harvest stalky crop, such as corn, irrespective of the distance between the rows and the direction of the rows relative to the harvester as it moves across a field. Similarly, it is sometimes necessary to harvest randomly planted crop. Therefore, there are instances where row placement or harvesting conditions would prevent the use of a conventional row harvester having forwardly facing stalk inlets spaced at non-adjustable positions corresponding to a certain row spacing. For example, the rows of crop may be spaced too narrowly or widely apart to allow entry of the stalks into the spaced inlets of the conventional row header. This problem may occur when the farmer has planted crop at various row distances.
Accordingly, forage harvesters have been developed to harvest randomly planted crop or row crop irrespective of the distance between the rows and the direction of the rows relative to the harvester. Non-row-sensitive forage harvesters typically include a chopper for chopping severed stalks (a so-called "chopping box") and a harvesting header extending forwardly from the chopping box and defining a working width. The header includes at least one rotatable cutting disc for severing the crop across substantially the entire working width as the harvester moves across the field. Thus, all the crop located in front of the harvester, irrespective of row placement, is severed by the disc. A conventional non-row-sensitive header also includes at least one rotatable transfer device coaxial with the cutting disc, with the device serving to move stalks severed by the disc toward the chopping box. The transfer device often comprises a drum-shaped body having a plurality of circumferentially spaced fingers arranged in vertically spaced rows along its cylindrical periphery. Alternatively, the device may comprise a plurality of vertically spaced coaxial discs provided with a plurality of peripheral recesses for receiving the stalks.
In any case, conventional non-row-sensitive forage harvesters have problems with delivering the severed stalks to the chopping box. This problem is attributable in part to the fact that a path is defined between the transfer device and the chopping box in which stalk movement is uncontrolled and relatively disorganized. Particularly, conventional transfer devices disengage the severed stalks after moving the stalks to a location spaced from the chopping box. The stalks must consequently travel to the chopping box for some distance without being directly acted upon by the devices. It is believed that in a conventional non-row-sensitive harvester, the stalks are caused to flow along the uncontrolled path by their own momentum or the pressure exerted by inflowing, subsequently severed stalks. This is particularly troublesome since it is along the uncontrolled path that the severed stalks are pushed down into a generally horizontal orientation so that their butt ends are presented to the chopping box inlet.
The resulting disorganized flow of stalks toward the chopping box tends to clog the harvester and, in some cases, may jam or damage harvester components. The lack of control between the transfer device and chopping box may also result in the loss of crop. These problems are magnified in adverse harvesting conditions such as downed crops, entangled masses of stalks and undergrowth, variances in stalks sizes, heavy foliage and numerous or large ears on the stalks, tall stalks, etc. These problems are also more evident in high capacity harvesters having more than one transfer device and coaxial cutting disc.
Non-row-sensitive harvesters have been provided with rotatable conveyor drums positioned between the chopping box inlet and the transfer device for feeding the severed stalks to the chopping box. The conveyor drums rotate about an axis offset from vertical so as to angle upwardly from the transfer device for elevating the butt ends of the severed stalks to the chopping box inlet. However, the conveyor drums fail to positively control the movement of each severed stalk from the transfer device to the chopping box inlet, but rather simply exert a rearwardly directed force against the stalks. Additionally, such a configuration demands that the severed stalks be transferred from one drum to another as they move toward the chopping box, which is inherently troublesome.
Consequently, even harvesters utilizing conveyor drums still encounter problems with the movement of severed stalks between the transfer devices and the chopping box inlet which, as discussed above, may lead to clogging, jamming or damage to the harvester components. Further, because it is difficult to coordinate the throughput rates of the conveyor drums with the rates of the transfer devices, there is some risk that the transfer devices will overload the conveyor drums.
Other problems with conventional non-row-sensitive forage harvesters include wrapping of material, such as stalks or trash, around the transfer devices or conveyor drums. Although conventional harvesters have been provided with stationary elements for stripping material from the devices and conveyors, the stripping elements tend to collect material which may cause clogging or lock-up situations. These problems are magnified in wet crop conditions.